When your stepdaughter fucks your son, you might feel bad about yourself. Stepmothers tend to be more invested in changing their stepchildren's behavior than their own children, so they are more likely to enforce rules, require proper hygiene, and instill discipline than their own children. Stepfathers are less invested in these same things, and they are more likely to abdicate their parental responsibilities or act resentfully. Broken relationships aren't good for any parent, but they can be detrimental to stepchildren as well.